Chemical Communications Blog

Catalytic reaction cascades present a neat, efficient way to synthesise valuable organic molecules. However, their success relies upon the compatibilty of the reactants and catalysts involved, and identifying this requires ingenuity and experimentation.

Now Darren Dixon and co-workers at the University of  Oxford have reported a one-pot nitro-Mannich/hydroamination cascade for direct synthesis of 2,5-disubstituted pyrroles from imines and nitro alkynes. The reaction is catalysed by base and a gold(I) catalyst, and has been optimised to achieve yields up to 86%.  

To find out more download the ChemComm communication, which is free to access until April 28th

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Several pyroglutamate-based natural products have been found to exhibit potent anti-cancer and anti-microbial properties. Although their syntheses have been a focus of research for many groups, their is still room for improvement in the development of highly tunable methodologies for the diverse functionalisation of the pyroglutamate ring.

Venkatram R. Mereddy and co-workers have  developed a novel and exceptionally short methodology for the synthesis of such functionalised pyroglutamates via alkylation of amino acid-derived iminoesters with allyl bromides or allyl acetates, easily obtained by Bayliss-Hilman reaction.

To learn more download the ChemComm communication, available for free until March 28th

Synthesising intriguing bioactive natural products in the most expedient and atom-efficient manner remains a highly active and competitive field of research. Cortistatins A and J, first isolated from the marine sponge Corticium simplex in 2006, have been identified as effective anti-angiogenics, which studies have found could suppress cancer recurrence when given in conjunction with traditional cancer drugs.

Lok Lok Liu and Pauline Chiu at the University of Hong Kong have reported a concise, high yielding, asymmetric synthesis of the pentacyclic framework of the cortistatins, in 12 steps from commercially available starting materials. Their synthesis employs a highly diastereoselective intramolecular [4+3] cycloaddition of epoxy enolsilanes as the key step and brings them close to their ultimate goal.

To find out more, download the ChemComm communication for free up until March 28th

To start a discussion, leave your comments below and for a related blog post see the Totally Synthetic blog pages.

The hugely important field of transition metal catalysed C–C cross-coupling has come a long way over the years, but efficient coupling between Csp² and secondary Csp³ centres remains a challenge. To achieve just that, Michael Organ and his colleague Selcuk Calimsiz (York University, Toronto) have developed and used a bulky Pd-NHC (N-heterocyclic carbene) catalyst called Pd-PEPPSI-IPent.

In the reactions of secondary alkylzincs with a variety aryl or heteroaryl halides, this catalyst provided excellent regioselectivity for the branched product over the isomerised unbranched product, far outperforming the less bulky Pd-PEPPSI-IPr analogue.

To see the impressive scope of the reaction download the ChemComm communication for free up until 7th March 2011 and leave your comments below.